Radio receivers and transmitters integrate together low noise amplifiers, mixers, RF oscillators, filters, variable gain amplifiers, and high-power driver amplifiers. Each system operates over a wide dynamic range and requires extensive isolation.
In practice, inadequate isolation due to circuit or layout coupling limits the achievable dynamic range. Circuit coupling can occur through circuits shared by multiple components, such as reference circuits, as these circuits offer only limited isolation. For example, strong signals processed by low noise amplifiers, RF Oscillators, and PA drivers can affect common bias sources. It would therefore be advantageous to have reference circuits that are isolated from other system components.